1. Field of the Invention
The present invention relates to an apparatus for the treatment of contaminated air or surfaces in order to remove or oxidize odoriferous gases and deleterious compounds therefrom through the utilization of ozone droplets, and more particularly pertains to the treatment of manufacturing facilities, wet wells, sewage installations, buildings, equipment and industrial installations and diverse locales subjected to foul air, in order to remove noxious and potentially toxic vapors and impurities from the air or surfaces through the dissolution of ozone in water to form droplets, and spraying the resultant mixture into the air as a fine aqueous mist. Moreover, the invention is also directed to the provision of a process for eliminating odoriferous or noxious vapors or gases and harmful constituents entrained therein from a volume of contaminated air or surfaces through the utilization of ozone dissolved in water by the employment of the inventive treatment apparatus.
The employment of ozone in connection with the use thereof in apparatus and processes for eliminating malodorous and oxidizable constituents from their presence in the air or on surfaces is imbued with various advantages, of which a primary advantage resides in the simplicity of the processes which are required and in the apparatus for implementing the processes. The only basic requirement is the provision of a substantially closed chamber or space which contains the air which is to be treated by means of an ozone generator, and also the elimination of any necessity for the installation of generally expensive filters which require periodic cleaning and replacement, and wherein a further advantage resides in that the products from the vapor which has been purified by the ozonation are generally constituted of carbon dioxide, water soluble sulfate and water which consist of harmless substances. These enclosed spaces or chambers may be lift stations of wet wells, manufacturing locales, scrubber ducts, contaminated buildings and equipment contained therein, among numerous other applications.
Although it is widely known to employ high concentration of ozone for the elimination of odors from air, the latter of which has been fouled by noxious constituents and/or malodorous gases or vapors, for example, such as hydrogen sulfide gas, or other sulfur-containing vaporous substrates, such as mercaptans, dimethylsulfate, and the like, the ozone must be generally evenly dispersed throughout the volume or space of the air being treated and specific concentrations of ozone maintained until the malodorous and noxious constituents entrained in the air have been oxidized, and in effect, odor-neutralized. Such high concentrations of ozone segregate by density such that ozone, being of greater density than air, settles to the bottom of the contained space, corroding the bottom equipment and absenting the upper reaches of the confined space, thereby not eliminating the light malodorous compounds in the top of the head space.
In order to overcome any disadvantages which are encountered in the odoriferous or noxious gas-removal treatment of air, by means of ozone in a preferably continuous mode, advantages may be taken by the ability of ozone being soluble in water, whereby the reaction of ozone with water forms various free radical moieties such as hydroxyl free radicals, superoxides and the like and peroxy radicals which, in turn, further reacts to form hydroperoxide free radical. These compositions comprising hydroperoxide and hydroxyl are strong oxidizers which will readily react with numerous impurities, including microorganisms such as bacteria and viruses, and destroying these by oxidizing the latter and or interrupting their reproductive mechanisms, and wherein ozone is quite normally injected into municipal water supplies as a purifier and disinfectant. Furthermore, it is also important to use ozone in the treatment of lift stations in wet wells, such as those in wet sewage treatment plants, and also in industrial and commercial installations in which waste or polluted water emits odoriferous gases, not to mention constituents which are entrained in the gases such as bacteria and viruses, as well as pollutants encountered in scrubber ducts, contaminated buildings and other manufacturing and industrial installations, and surfaces thereof, and whereby the odors which are generated are extremely objectionable to persons in the immediate vicinity or environs of the particular installations or facilities being treated. In order to be able to eliminate or neutralize the noxious or odoriferous gases which are emitted from the various installations or wet wells, a process of spraying water containing dissolved ozone into the air in the form of sprays of very fine droplets is advantageous in eliminating these gases and impurities in the air in comparison with simply introducing a flow of ozone into the air. The reactions between the ozonated water sprays and gases or impurities contained in the air is extremely rapid, and serves to remove any concerns as to the ozone constituting a health hazard in the environment inasmuch as the ozone contained in the air is generally less than 0.5 parts per million, which is considered to be a permissible level when absorbed by humans.
Furthermore, the dispersing of a spray containing extremely fine droplets of water in which ozone into the air in order to remove odoriferous gases and contaminants is accomplished by causing gaseous ozone to come into contact with the water, and the absorption thereof depends upon the size of the contact surface between the gaseous ozone and water, which also increases the speed at which ozone is absorbed by water in proportion to the size of the contact area.
2. Discussion of the Prior Art
The utilization of spray-forming nozzles which atomize ozone in water has been already well developed in the technology, and industry, whereby patents by the present inventors are of particular significance and advantage. Thus, Erb et al., U.S. Pat. No. 5,337,962 discloses an atomizer device which reduces flowable liquid into an ultrafine dispersion of liquid particles in a propellant gas, and whereby an atomizing spray of ozone may be formed to treat odoriferous or noxious gases in order to remove any odorous properties and/or impurities therefrom.
A more recent development in providing an odor controlling atomizer nozzle device which employs ozone dispersed in water to form minutely sized droplets clearly provides the advantages of rapidly and extensively eliminating odoriferous gases, such as hydrogen sulfide, from the air which has been contaminated with these gases emanating in enclosed spaces from sources such as, for instance, wet wells or diverse locales, is disclosed in Resch et al., U.S. Pat. No. 6,076,748. The disclosures of both of these patent publications are herewith incorporated in their entirety by reference into the present application.
Although the atomizing nozzle disclosed in Resch et al., U.S. Pat. No. 6,076,748 clearly provides an advantageous structure when implementing a process of purifying air, the degree of being capable of removing odoriferous gases and potentially any pollutants in the air stream which are generated in enclosed spaces is generally at an efficacy of up to approximately 90%. Typically, municipal sewers which may include lift stations comprising wet wells may contain of up to 1,000 ppm of H2S (hydrogen sulfide) gases, although a more typical well may only contain about 50 ppm. These ozonated water spray treatments, although normally adequate in purifying the air in eliminating the odoriferous gases may not fully meet the requirements of more sophisticated customers or residents domiciled in the vicinity of such wet wells, since the high dosage levels of hydrogen sulfide gases generated in some of the wet wells may only be eliminated by up to a 90% reduction, and multiple atomizing nozzles of that type also fail to provide a reduction of the problems emanating from only a 90% improvement to targeted improvements of 99% to 100% in ideal situations. Consequently, a problem which is required to be solved in purification of air and removing odoriferous or noxious oxidizable gases therefrom, for example, such as those constituted of hydrogen sulfide gas or other sulfur-containing gases, or toxic nitrogen containing gases, such as NH3, is to facilitate a degree of purification of the air of up to 99% or 100%; and also to enable residual ozones to be exhausted to acceptable levels, and also to enable the use of industry acceptable measuring apparatus which will sense a true reduction in hydrogen sulfide or other sulfur-containing gases and contaminates contained in the air.